The purpose of the Cost Analysis Section (CAS) is to provide technical assistance to Cancer Prevention Research Program (CPRP) investigators who include cost analyses in their research. Toward this end, the CAS will develop a general approach to estimating and analyzing the costs of cancer prevention research trials and interventions, and work with project investigators in applying it to participating projects. The resulting methods are intended to be applicable to efficacy as well as effectiveness studies of cancer control interventions, and to the analysis of research as well as intervention costs. The methods can be applied during the planning stages of a research project, or as part of an evaluation plan. The specific aims are to 1) develop a spreadsheet-based computer program to assist CPRP investigators with research design cost analysis, intervention cost evaluation, and budgeting; 2) develop sampling and accounting procedures for use in cancer prevention research projects to collect project cost data, and using these data, estimate the unit costs of specific project activities; and 3) using the methods developed and the data collected, provide CPRP investigators with technical assistance to analyze the costs of their proposed research, and/or to estimate the cost-effectiveness of their cancer control interventions.